WASHINGTON — Liz Cheney dropped her bid for the Senate in Wyoming, saying "serious health issues" in her family have caused her to end her GOP primary challenge against Sen. Mike Enzi.

"Serious health issues have recently arisen in our family, and under the circumstances, I have decided to discontinue my campaign," Cheney said in a statement released Monday. "My children and their futures were the motivation for our campaign and their health and well-being will always be my overriding priority."

Cheney, a former State Department official in George W. Bush's administration, thanked her supporters and vowed to continue to fight for her beliefs.

"As a mother and a patriot, I know that the work of defending freedom and protecting liberty must continue for each generation. Though this campaign stops today, my commitment to keep fighting with you and your families for the fundamental values that have made this nation and Wyoming great will never stop."

Cheney, 47 years old and the eldest daughter of former Vice President Dick Cheney, upended Wyoming politics when she announced in July that she would take on Enzi, a three-term veteran. She had stressed in a campaign video that it was a time for a "new generation" of leaders in the Senate, began to criticize Enzi's conservative record, and said she would align herself with Tea Party favorites such as Sen. Ted Cruz, R-Texas.

Her campaign was a personal blow to Enzi, who counted Dick Cheney as a friend and said he had received assurances from Liz Cheney that she would not challenge him. Enzi, 69, now is likely to have an easier time getting re-elected in Wyoming, a Republican stronghold.

The Cheney campaign also divided Republicans in the state, with many prominent politicians such as Sen. John Barrasso and former senator Al Simpson siding with Enzi. Cheney's candidacy also split her family and exposed a rift with her sister, Mary, over same-sex marriage.

Mary Cheney, who is lesbian, and her spouse, Heather Poe, took to Facebook in November to criticize Liz Cheney's stance on "traditional marriage" after the candidate's appearance on Fox News. Dick Cheney and his wife, Lynne, issued a statement in support of daughter Liz.

From the start, Liz Cheney had to answer criticism that she was a carpetbagger in the state where her father had made his political mark as a member of Congress.

She had moved from the Virginia suburbs of Washington to Jackson Hole, Wyo., in 2012. Last summer, a Wyoming newspaper reported she had purchased a fishing license well before the time allowed under state law. Teton County records also showed she and her husband, Phil Perry, were more than two months late in paying property taxes on their Wyoming home.

Liz Cheney's decision to abandon her campaign was first reported Sunday night by CNN. Her statement about quitting the race was first reported by Politico.